The airline advised, "Pilots who are preparing to configure and land have the potential to experience abrupt pitch up, slow airspeed, and approach to stall if conditions present themselves in a certain manner."

Southwest Airlines spokesperson Linda Rutherford said an earthen dam at the end of the runway was interfering with the signal being sent to inbound flights. Rutherford would not confirm if any of Southwest's recent flights into Buffalo experienced problems on approach.

"We often put out alerts on obstructions to a navigation aid," Rutherford told CNN.

She also pointed out, though landing on the same runway, Southwest Airlines flights approach runway 23 from the north, turning right, while the Colgan Air flight that crashed was approaching from the south turning left. Rutherford called that distinction important. View a Google Earth image of runway 23 »

The issue is caused by a geographic feature at the airport, a valley, "something we can't do anything about," said FAA spokeswoman Laura Brown. She said the "altitude reading makes it look like you're a lot higher than you are, because there is a valley there."

The feature has been noted on FAA charts for years, she said.

"As far as we can tell, there is no way this had any role in the accident," Brown told CNN. "It's not a navigation aid that would have applied to the approach."

The alert from Southwest Airlines advises pilots that the problem could cause the planes navigational system to interpret data "in such a way as to result in a nose-up pitch and loss of airspeed."

Flight data recorders obtained by the NTSB of the crashed Colgan air Flight 3407 show during its approach to runway 23, the twin turbo prop Dash-8 pitched up 31 degrees before going into a stall due to lack of airspeed.

Southwest Airlines Pilot Association told its pilots the "issue is being addressed on several levels in an attempt to address procedures, facilities, and communication regarding this matter."

The alert advises any pilots experience trouble to contact the association's safety office.